Showing papers in "Journal of Biological Chemistry in 1918"

The inorganic elements in nutrition

Abstract: EXTENSIVE investigations made within recent years and demonstrating the importance to human nutrition of minute quantities of various mineral elements were reviewed by Prof. E. V. McCollum, professor of biochemistry in the Johns Hopkins University School of Hygiene and Public Health, in a paper read at the University of Pennsylvania Bicentennial Conference on September 17.

The colorimetric determination of hemoglobin

Abstract: The method to be described for the determination of hemoglobin depends upon the comparison, in a calorimeter, of carbon monoxide hemoglobin solutions, one of which has a known hemoglobin content. Hoppe-Seyler (1) was the first to describe carbon monoxide hemoglobin and to make use of this stable combination for estimating the hemoglobin content of blood. He devised a “double pipette” for comparing the unknown carbon monoxide hemoglobin solution with the standard carbon monoxide hemoglobin solution, prepared from hemoglobin crystals; but the method never came into general use, because of the many technical difficulties involved. Haldane (2) suggested a much simpler method for comparing carbon monoxide solutions, using the apparatus employed by Gowers (3) for comparing oxyhemoglobin solutions with a picro-carmine standard. This apparatus was later employed by Sahli (4) who prepared an acid hematin standard by adding dilute hydrochloric acid to blood. A critical discussion of the various methods in use for the estimating of hemoglobin is beyond the scope of this paper. As Haldane (2) has pointed out, artificially colored solutions and tinted glass present great difficulties in standardization with a definite strength of hemoglobin solution. With a certain strength of color solution or tinted glass, it is possible to imitate quite perfectly the tint of a given hemoglobin solution provided the quality of light remains the same. Any variation from these standard conditions, either in quality of light or strength of hemoglobin in solution leads to serious errors. Haldane at-

The colorimetric estimation of cholesterol in blood, with a note on the estimation of coprosterol in feces

Abstract: During the past 6 years a number of different procedures have been utilized in the extraction of cholesterol from small quantities of blood for its ultimate calorimetric estimation. From the multiplicity of methods employed for the extraction process one would infer that they were not entirely satisfactory. Since1913 a number of these methods have been tried out in our laboratory. In connection with a study of the blood lipoids in obesity, carried out in collaboration with Dr. Kast, it seemed necessary to investigate further the question of a suitable cholesterol method. For some time now, however, we have employed a comparatively simple and very satisfactory method,’ which is described in the present paper. Grigaut2 was apparently the first to attempt the calorimetric estimation of cholesterol, using the Liebermann-Burchard reaction. 2 years later, Weston3 made use of the Salkowski reaction for a similar purpose. Since these reactions are very delicate they at once afforded a means of estimating the cholesterol in small amounts of blood, thus furnishing an impetus to this type of

The structure of yeast nucleic acid

Abstract: Levene and Jacobs have formulated the structure of yeast nucleic acid as a tetranucleotide. The facts that led up to their formulation were: 1. The formation of four nucleosides on neutral or ammonia hydrolysis. 2. The formation of simpler nucleotides on hydrolysis with dilute mineral acids. 3. The presence of a phosphorus to nitrogen ratio which agreed quite well for t.he tetranucleotide theory. 4. The ratio of amino to total nitrogen in nucleic acid was in harmony with the ratio required by the four bases, guanine, adenine, uracil, and cytosine. The mode of linkage between the individual nucleotides was at that time not determined, and in the graphic formula representing the nucleic acid the linkage of the nucleotides was of a provisional character and arbitrary in nature. Following that, the studies of Levene and Jacobs on thymus nucleic acid led to methods which permitted the separation and the study of individual monoand dinucleotides composing the complex nucleic acids. Levene and Jacobs then returned to the study of yeast nucleic acid, applying the experience gained on the thymus nucleic acids. They then directed their attention to the nucleotides obtained by acid hydrolysis of the yeast nucleic acid. A large quantity of the material was prepared and transformed into the brucine salt. Other work, however, made a demand on their energies, and the work on the nucleotides was somewhat neglected. However, in course of the present academic year the work has been resumed, There were on hand 125.0 gm. of the brucine salts when the work was begun.

The choice between adequate and inadequate diets, as made by rats

Abstract: The success with which animals living in their natural environment nourish themselves must depend upon the exercise of choices in which instinct and appetite play a significant part. When such individuals are transferred to conditions of domestication their freedom of choice, particularly in t’he case of captive or farm animals, is restricted. Their diet now becomes a problem for the husbandman who follows in part his observations on the actual feeding habits of the species and in part the dictates of special trials or experimental observations on the species in question. Many infants and children are likewise dependent upon a dietary regimen controlled or modified independently of their natural preferences. Man generally chooses his own food; but the selection is limited by a number of circumstantial factors which have led to the formation of so called dietetichabits. In discussing the origin of modern so called feeding standards, Armsby’ says:

A method for the determination of sugar in normal urine

Abstract: In a previous paper’ we described a procedure for t,he determination of sugar in normal urines based upon preliminary removal of the nitrogenous urinary constituents by means of mercury nitrate in the presence of sodium bicarbonate. The sugar was then determined in t,he filtrate by the use of picric acid and alkali under definite conditions. This method has been of considerable service. Frequent checkings by comparative determinations made upon the same filtrates by the Allihn gravimetric method which we have carried out have convinced us that the method is accurate for both unferment,ed and fermented urines. Duplicates by the calorimetric and the ,411ihn method practically always agree with 0.02 per cent on the sugar content of the urines. The mercuric nitrate method has, however, a serious drawback in the laborious technique involved, which has interfered with the general usefulness of the method. We have, therefore, const,antly kept in mind the development of a procedure which should permit of the determination of small quantities of sugar in urine without the use of so troublesome a technique. The method described in the present paper meets this requirement. It has been in constant use in our laboratories and elsewhere for about 2 years, and we now feel quite sure of its accuracy and reliability under widely varying conditions. While the present method retains the use of picric acid, it seems probable, as will be pointed out later, that the actual reaction takes place between the sugar and an unidentified derivative of picric acid.

A study of the carbon dioxide-combining power of the blood plasma in experimental tetany

Abstract: Recent investigations of the acid-base equilibria in pathological conditions have been slowly adding to our knowledge of the factors involved in their maintenance. Acidosis seems first to have caught the attention of investigators, probably because of the greater frequency with which it is encountered. Recent studies by Wilson, Stearns, and Janney (I), Wilson, Stearns, and Thurlow (2) have directed attention to the condition of alkalosis. These investigators have found that in dogs following parathyroidectomy the equilibrium between acids and bases is displaced in favor of the bases, and that in tetany which develops after such a procedure there is well marked alkalosis. This was developed in a study of the hemoglobin dissociation, and of the alveolar air in dogs following thyroparathyroidectomy. From an uncompleted series of experiments on dogs, undertaken to study the gastric secretion in tetany, the following data regarding the carbon dioxide-combining power of the plasma are taken. These data give confirmation to the conclusions of Wilson and coworkers with regard to the results following parathyroidectomy. Furthermore, studies were made on dogs in which tetany was induced by various operative procedures on the stomach. In these latter cases changes in the acid-base equilibrium were noted similar to those following parathyroidectomy. The method of investigation chosen was simple. The ability of the plasma to combine carbon dioxide at alveolar tension, deter-

Experimental scurvy of the guinea pig in relation to the diet

Abstract: In 1895, Theobald Smith reported that guinea pigs died of a peculiar hemorrhagic disease when fed on a cereal diet without succulent vegetables. More than 10 years later, Holst and Frolich directed attention to the similarity between this malady in the guinea pig and human scurvy. Whether the etiological facton is identical in both these syndromes is a point that still remains to be definitely settled. However, there are many points of resemblance between the two, since the clinical pictures are practically alike, except that affection of the gums is not usually found in the guinea pig. It has also been suggested that swelling of the joints in the same animal might be ascribed to a condition of rickets (Gerstenberger, 1918). It has long been recognized that scurvy is a nutritional disease, for numerous authors testify that its appearance was preceded by a monotonous diet of some peculiar nature. Also, though the pathogenesis is still rather obscure, the means for the cure of this malady were known for a long time: a change in diet to fresh food-especially green vegetables-would initiate a prompt improvement and speedy cure. In the minds of observers in the earlier studies of the subject infection and toxemia played a prominent role as the causative agent. Later, with the advent of the vitamine theory to explain deficiency diseases, it was assumed that the absence of an antiscorbutic substance in the dietary was responsible for the nutritional failure. More recently, owing to the claims of McCollum and his coworkers, the existence of an antiscorbutic vitamine is questioned. Indeed, they deny that scurvy is a deficiency disease in the true meaning of the term. They ascribe it to some defect in the texture of the diet; that is, unsatisfactory physical factors induce a chain of circumstances which result in damage to the wall of the alimentary canal and a consequent toxemia. It is now generally agreed that an exclusive diet of cereals or other plant seeds will cause a failure of nutrition of the guinea pig with disturbances

Gasometric determination of the oxygen and hemoglobin of blood

Abstract: The apparatus described in a previous paper’ for determining the carbonic acid content of plasma may be used with equal facility for determining the oxygen content and the oxygenbinding capacity (hemoglobin) of blood. For determinat,ion of the oxygen capacity as a measure of the hemoglobin 3 or more cc. of blood are introduced into a separatory funnel or bottle and distributed in a thin layer about the inner wall, so that maximum contact with the air and complete saturation of the hembglobin with oxygen are assured. The vessel is rotated for a few minutes so that the blood is kept in a thin layer, or it may be shaken for 15 minutes or longer on a mechanical shaker. The saturat,ed blood is transferred to a heavy testtube or cylinder. The blood gas apparatus is now prepared by introducing into it five drops of redistilled caprylic alcohol and 6 cc. of ammonia solut,ion made by diluting 4 cc. of concentrated ammonia to a liter. If saponin powder is available, as much is added to the 6 cc. of ammonia while in the cup of the apparatus as will st.ick to the end of a glass rod. After the ammonia ha.s been introduced into the 50 cc. chamber of the apparatus the latter is evacuat.ed in the manner described in the previous article, and the air is extracted from the ammonia solution by shaking for about 15 seconds. The extracted air is expelled, and the extraction completed to make sure that no air is left in the solution. Finally, about 2 cc. of the air-free ammonia are forced up into the cup of the apparat,us. The aerated blood is now thoroughly stirred with a rod to

The distribution of phosphoric acid in normal human blood

Abstract: In the last few years considerable evidence has accumulated to show that the lipoid compounds of phosphoric acid of the type of lecithin are probably of great importance in the metabolism of the fats. For example a marked increase has been observed in lecithin in the blood and particularly in the corpuscles during fat absorption (1). In those pathological conditions where the blood lipoids are abnormal, as in diabetes (2) and anemia (3) the values for lipoid phosphorus follow in general those for total lipoids. The increase in fat which takes place in the blood of hens at the time of egg production has been found to be accompanied by increased lipoid phosphorus (4). Then there is the very significant observation of Meigs and Blatherwick (5) that during the secretion of milk in cows the blood leaving the milk gland contained less lipoid phosphorus and more inorganic phosphorus than the blood entering the gland. Also that the decrease in lipoid phosphorus was sufficient to account for the fat of the milk-clearly indicating that the milk fat originated in the lipoidphosphorus compounds of the blood. On the other hand, in very severe diabetic lipemia (6), the increase of lipoid-phosphoric acid compounds’ was relatively less than that of some of the other lipoid constituents; e.g., cholesterol. The question arose whether the reason for the relatively low value may have been the lack of phosphoric acid available for lipoid combination. This involved the general problem of the relation of the lipoid phosphoric acid to other forms of organic phosphoric acid in the blood. These and

Respiratory regulation of the co2 capacity of the blood iii. the effects of excessive pulmonary ventilation

Abstract: In the light of present knowledge it appears probable that many, perhaps most, of the functional disturbances induced. by anesthesia are due to the production of an abnormal CO2 capacity (alkaline reserve) in the blood, or to deeper effects of which the CO2 capacity is an index. At present such effects are generally interpreted as “a19dosis.~’ Our observations show that, at least under ether, they are of a very different origin. Morris.9 has shown that in patients under ether a lowering of the alkaline reserve of the plasma occurs. On the basis of some preliminary experiments on dogs Prince and the authors2 have verified Morriss’ observation and have obtained results indicating that the effect is due to the respiratory excitement induced by ether. An abnormally great amount of CO2 is ventilated out of the blood by the excessive breathing and the CO2 content is thus lowered. Sometimes when this blowing off has been very rapid the result is failure of respiration: apnea Vera. When the blowing off is less rapid but is prolonged another change occurs which (as Prince first pointed out to us) is of a compensatory character. This consists (as set forth in general terms in the first paper of this series) in a decrease of the COzcombining power (alkaline reserve) of the blood. The simplest supposition upon which to explain it is that when the alkalinity